# SDR ASAA2021012833956

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 28, 2021
- Submitted: January 30, 2021
- Operation: Air carrier
- Aircraft: [N471AS](https://openairdocs.org/aircraft/N471AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 41703
- Aircraft time: 23,970 hours, 7,649 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Modulating Valve
- Part number: 3989083
- Part serial: 5674
- Condition: Inoperative
- Location: Left Ecs Bay
- Part time: 66,485 hours, 24,093 cycles
- Stage of operation: TX
- How discovered: V
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021012833956

## Discrepancy

AFTER ENGINE START DURING MASTER CAUTION RECALL CONT CAB ZONE TEMP LIGHT ILLUMINATED, PER QRH LIGHT EXTINGUISHED WITH MASTER CAUTION RESET.  GROUNDED-YES.  REMOVED AND REPLACED FLIGHT DECK ZONE MODULATING VALVE, REF B737-900 AMM 21-61-21.  OPERATIONS AND LEAK CHECKED GOOD.  CLEARS MEL 21-21G SEAMC JEREMY NOTIFIED PLACARD REMOVED.

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